This invention relates to a data transceiver, and more particularly to an FSK data transceiver which is capable of long distance data communication.
Conventionally, many kinds of radio communication methods are used for a transceiver system. The most familiar radio communication modulation method is amplitude modulation (AM). The AM method is widely used in citizen band radio transceivers. The frequency modulation (FM) method is also widely used for radio transceivers. These radio communication methods have sufficient performances for audio communication in the case of short distance communication to a certain extent, but are still insufficient for long distance communication and for reducing power consumption. Further, Morse telegraphy communication systems are also insufficient for long distance communication and for reducing power consumption. In order to improve the performances in long distance communication, the narrow bandwidth signal system has been introduced, but has not resulted in any improvement because of the oscillation frequency turbulence or drift and unsophisticated narrow band techniques.